r/SteamOS • u/McRovin22 • 4h ago
question Cost of having HDMI-CEC for DIY Steam Machines?
Is getting the HDMI CEC working worth the trade off? When I used the Ugreen adapter(via display port) to activate the HDMI CEC, my steamos home screeen was flickering whenever I turned on VRR and AMD freeSync on my TV. I switched to the HDMI port without the adapter and everything ran smoothly. I have an LG C5 and I don’t mind turning on my TV with the tv remote so I can get the best display settings. Does anybody have the same experience?
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u/mango_carrot 3h ago
The adapter doesn’t play nicely with VRR/120hz in most cases that I’ve seen (mine too). Personally I only ever play at 60fps so I’m happy with the trade off of having CEC instead of the other features.
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u/jollyjoeroger1997 3h ago
Yes on the compression with DSC at high refresh. 4k 120hz HDR with the adapter and can only get 8-bit color. Drop it to 60hz and it goes up to about 12-bit
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u/dannykid722 3h ago
The adapters are active because they are supposed to handle the DSC signal conversion. To my knowledge your televisions support of DSC is irrelevant and the subsampling is based on what the adapter outputs. I haven't had issues with flickering, but handshaking has been an issue if it is forced in rapid succession by opening and closing exclusive display apps. But once an app has a successful handshake it's been pretty rock solid.
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u/Low_Excitement_1715 3h ago
DSC doesn’t come into it with the uGreen adapter. It’s converting full bandwidth DisplayPort to HDMI 2.1. The client never sees any reason to enable DSC, because DP doesn’t need it.
Once kernel 7.2.0 releases, this will start being a more and more abstract issue. I’m sure Valve is planning to backport the updated amdgpu driver, too. AMD didn’t enable native VRR in the first release, just FRL and some other basics, but we should have fully functional HDMI 2.1 on AMD hardware before the end of the year.
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u/christofos 3h ago
HDMI 2.1 full bandwidth isn't even available yet on Linux so you don't have much of a choice at the moment. It's supposedly going to be rolling out in the 7.2 kernel next month.
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u/captainstormy 3h ago
The point of the adapter isn't really for CEC. On Linux with AMD cards HDMI doesn't work because of licensing issues. So really you should be comparing the numbers against HDMI 2.0 because despite the fact that all the hardware involved is 2.1 (assuming your TV and cable are) the software is still only going to be using 2.0.
HDMI 2.0 only supports 4K60 and IIRC less than that if you want HDR.
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u/McRovin22 3h ago
So does turning on VRR and AMD freeSync do anything for my visuals?
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u/captainstormy 2h ago
If you are using the DP adapter absolutely. If you are using HDMI on Steam OS You just have to reference the HDMI 2.0 spec to know what is possible.
IIRC VRR can work but often doesn't because the spec runs out of bandwidth at 4K very fast. Freesync I believe will work fine with it but I'm not 100% sure.
There is an update in Linux Kernel 7.2 to make HDMI 2.1 work on AMD cards. Assuming the HDMI Forum doesn't take legal action to stop that. AMD didn't pay them to use the spec, but it was reverse engineered instead to make it work. No clue when that will make it's way into SteamOS though.
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u/McRovin22 2h ago
So adapter with VRR and Amd FreeSync off is better? Will it activate HDMI 2.1? My home screen was flickering with the adapter on.
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u/captainstormy 1h ago
The Adapter converts DP 1.4 to HDMI 2.1 yes. But VRR and FreeSync should also work just fine. The wife and I have had a Home built Steam Machine for a while and I recently built 2 more for friends in the past month. All using the Adapter and none have flickering issues.
Are you using the Active adapter and not the Passive one? It needs to be the Active one to work properly.
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u/McRovin22 1h ago
This is what I use. https://a.co/d/0aXy9Did paired with https://a.co/d/08wR1cva.
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u/captainstormy 1h ago
That is the same adapter all 4 of us are using so that shouldn't be an issue. The HDMI cable should be fine too assuming it is what it says it is. All 4 of us are using a UGREEN brand cable too but that shouldn't be neccessary.
It might be some weirdness with the TV too possibly but I'm not sure.
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u/Adrian97c 1h ago
Link to active ?
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u/captainstormy 1h ago
This is the one that everyone agrees is the best.
https://www.amazon.com/dp/B0FQCF62CD
I did use a different one from another brand before it and it was kinda dodgy. Never had any issues with the UGREEN one.
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u/Adrian97c 1h ago edited 1h ago
Currently I can get 4k/120/hdr from just hdmi cable from 9070xt to 4k 165hz capable display. So what would this adapter help me do?
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u/captainstormy 1h ago
On SteamOS?
I don't see how that is possible. HDMI 2.0 literally doesn't support that.
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u/Adrian97c 1h ago
Soon as I get home I can make a quick vid clip to show.. my setup does include a 4 to 1 hdmi VRR/144hz/hdr pass switcher. I have ps5 pro, switch 2, steamOS amd machine going into it, then the out of adapter goes into elgato 4k x capture card, which goes to monitor & my mac (where I use as a stream pc). Here is the adapter I use (not sure this is why I’m able to get hdmi2.1 function from SteamOS Amd), all chained devices are 2.1 enabled. 8K@60Hz 4K@120Hz HDMI2.1 Switch 4... https://www.amazon.com/dp/B0CXH9M3KC?ref=ppx_pop_mob_ap_share
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u/One-Luck-1429 2h ago edited 1h ago
I came to the conclusion that it was not worth the tradeoff due to finnicky support for VRR. I was evaluating for my upcoming Killdozer, a top of the line SteamOS box which will benefit greatly from uncompressed HDMI 2.1 and VRR.
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u/SorcererOfLies 1h ago edited 1h ago
While the Pulse one adapter does only 60hz I went around it by plugging it like this in my bazzite pc:
TV HDMI 2 > Pulse One CEC adapter > NO CONNECTION TO PC's HDMI PORT, ONLY USB
TV HDMI 1 > GPU HDMI1 port (doesn't matter which one for my GPU)
Then with some scripting I made it so the TV detects the Pulse One output as HDMI 1 and now I have 4k120hz with automatic CEC TV wake and HDMI 1 select on PC wake/startup.
I don't know if it you could do the same on SteamOS but I imagine the physical setup to be similar. I have no experience with the UGREEN adapter either. Also HDR is on, but no VRR, waiting for support for that to come.
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u/Adrian97c 3h ago
How do I make my built SteamOS pc to turn on by pressing the Steam button on the Steam controller?
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u/McRovin22 3h ago
List all of your pc parts, steamos and ask google AI. It will guide you through everything. Bios and scripts
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u/Adrian97c 2h ago
Going to try that. I’m older & need to embrace AI more as a learning tool. Im familiar with bios, but scripts & konsole commands not so much.
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u/McRovin22 1h ago
I am old too, almost 42 years old. The last PC I built was maybe 13 years ago. I cannot do PC gaming anymore on a gaming chair so I built this DIY steam machine for the living room. https://www.reddit.com/r/SteamOS/s/sqi5XKCweJ
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u/Strange_Passenger814 2h ago
Also removed the adapter. The minor convenience of CEC wasn’t worth it for me. LG G3 with Reaper 9060xt.
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u/Pawl_ 2h ago
As confirmed by my previous post here and many others:-
You can get not only CEC but since HDMI2.1 support is still not here, 10bit 4k 120hz with VRR and HDR.
It’s a no brainer and it’s only 15-20euros.
Yes you only get DP1.4 but chatGPT is essentially just mishmashing sources of info. It even suggested not to get it for me until I got convinced on Reddit.
https://www.reddit.com/r/SteamOS/s/qqlshb7pV7 my other post here
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u/iSeeShiny 2h ago
im using G5 tv and direct HDMI and still only 4.2.0 and 8bit. at 4k 60 or 120. also why would i want to play on pc at 60hz? if wanted do that ill just go play on my ps5. lmao
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u/Dismal_Ad2727 1h ago
A better, less popular option imo is using pulse eight hdmi cec adapter.
It’s limited to hdmi 2.0 only if you use the stock cable but plug in a regular hdmi 2.1 cable on both ends and it works at full bandwidth. I tested using 2 anker hdmi 2.1 cables on a Samsung tv. Excessive cable length might also cause issues I believe.
The issue now is it takes some non trivial amount of setup to install and use the adapter properly as opposed to plug and play from the dp to hdmi adapter.
https://github.com/Twsts/steamos-cec-toolkit is close but only supports the ugreen adapter now.
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u/therepfella 35m ago
Try the cable matters one, ugreen specs were not great when I looked. I haven't plugged into my tv yet but I believe it addresses most if not all the shortcomings you mentioned.
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u/Zonkeyy 3h ago
so dont use freesync, its ass. dont use vrr, its also ass.
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u/sertaes 3h ago
What is this based on? Might be the worst opinion I’ve seen on here.
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u/Zonkeyy 2h ago
every time of tried vrr (tv or monitor) the implementation is absolute ass and you can see/feel the refresh rate changing. ive tried freesync with many different monitors that said its supported, every monitor flickers like crazy wth freesync - not to mention (though its rare!) some games flat out dont support it.
anecdotal, sure. if it works for you then thats great. but all my experience with them has been just awful.
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u/sertaes 23m ago
I’ve never had an issue like that with it on any system or even heard anyone with negative things to say about it.
Of course you can see the refresh rate changing in the sense that lower frames will still be delivered slower because they’re being shown as they are completed.
But you need to know that this is pretty much just a you issue that isn’t worth you expressing because you’re going to have people telling you you’re wrong and it does work because it works great 99% of the time on pretty much all setups.
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u/McRovin22 3h ago edited 3h ago
Doesn’t VRR and AMD freeSync matches your GPU’s refresh rate with your TV for the smoothest and best visual experience? Is this just a myth?
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u/jca3746 3h ago
Nah, not for me personally. For the longest time, I’ve played 60hz at 4k with no HDR because that’s all SteamOS could support. I tried work arounds like DisplayPort to HDMI adapters, but they were finicky at best.
Now I’m able to do 4K 120hz HDR with zero issues. I’ll wait until valve can get something baked in.